Thanks for posting this. I knew that i could stream the system sound to a single airplay speaker...
but my problem is that only iTunes can select multiple speakers (apart from 3rd party software) and this is what i liked... as i also was able to control the volume for all the 5 Airplay speaks comfortably from one app...
hope this is just a bug and will be fixed soon and not a legal issue...
and btw, i think it is absolutely worth posting that you can confirm the issue... as more and more people seem to experience the same problem, it becomes obvious that it is a system side bug not a single isolated issue... i personally find it most of the times pleasing to know that it is not me or my mac only... because the chances of a fix are much higher... 😉
cheers